NPS Mediated Control of Fear Expression and Extinction: Role of Intercalated GABAergic Neurons in the Amygdala Kay Jungling, Thomas Seidenbecher, Ludmila Sosulina, Jorg Lesting, Susan Sangha, Stewart D. Clark, Naoe Okamura, Dee M. Duangdao, Yan-Ling Xu, Rainer K. Reinscheid, and Hans-Christian Pape

Intra-amygdala injections of NPS block fear- potentiated startle fear ↓ effect of NPS independent of locomotor activity Fear potentiated startle – Separate out NPS anxiolytic effect from locomotor effect bi-lateral amygdala NPS injection Fear potentiated startle protocol then motility boxes

Fig 2 Effective Dose

Identification of a NPS Responsive Circuitry Shaping Amygdala Activity via the Endopiriform Nucleus MF0E MF0E NPS stimulates GABAergic input of BLA projection neurons NPS effects in BLA interneurons NPS stimulates glutamatergic input of BLA interneurons NPS stimulates glutamatergic input of BLA projection neurons

Fig 5: Effects of mechanical circuit dissection (B) Cuts detaching endopiriform nucleus from BLA eliminate NPS action upon sIPSCs in BLA projection neurons (C, D) Only dissection in between EPN and BLA diminish (C) amplitude or (D) frequency ratio: NPS/control significantly

Fig 7: Behavioral effects of NPS -NPS into EPN.1 nmol NPS effective dose here

Endopiriform Nucleus shapes BLA activity/response NPS in EPN controls neural activity of BLA NPS exerts direct action (mech) on EPN that ↑ Glu transmission EPN required for NPS modulation of GABA A feedback & feedforward inhibition of BLA Conditioned fear expression – NPS to EPN ↓ contextual (where) but NOT cued (what) fear memory in mice

Jungling Intro Injection of NPS into BLA – anxiolytic effect – acute reduction in general anxiety and – accelerated extinction of conditioned fear – injection of the NPS receptor antagonist SHA 68 exerted functionally opposing effects. NPS ↑ glutamatergic synaptic transmission to intercalated GABAergic neurons of medial paracapsular cluster via a presynaptic effect – involving principal neurons in the LA

medial paracapsular cluster Source:

Intro Cont. NPSR’s densely expressed in the mouse BLA – at single-cell level, in LA principal neurons – Not in paracapsular GABAergic neurons

Methods C57BL/6J mice, 8-12 wks old Bilateral injections into BLA/LA One animal per behavioral test/drug group Open field, EPM, dark-light test, fear cond. Amygdala coronal slices, whole-cell patch clamp

Figure 1 Effects of NPS in the LA/BLA on generalized anxiety behavior in the open field and elevated plus maze

Fig 2 Effects of NPS in the LA/BLA during retrieval and extinction of conditioned fear

Fig 3: Target specific effect of NPS on evoked EPSCs mpara neurons provide a feedforward inhibitory gate for signals between BLA and CeA

Fig 4: Lack of NPS modulatory influence in LA Principle Neurons (PN) and LA local GABAergic interneurons (IN)

Fig 5: NPS reduces failure- rates of glutamatergic transmission to mpara IN

Fig 6: Presynaptic site of NPS modulation

Fig 7: NPS receptor expression in the amygdala opt: optic tract BLA: basolateral amygdaloid complex, anterior part BMA: basomedial amygdaloid nucleus, anterior part MeAV: medial amygdaloid nucleus, anteroventral part ACo: anterior cortical amygdaloid nucleus ic: internal capsule DI: dysgranular insular cortex GI: granular insular cortex AIP: agranular insular cortex, posterior part LaDL: lateral amygdaloid nucleus, dorsolateral part DEn: dorsal endopiriform nucleus

Fig 8: NPS enforces feed forward inhibition on principal neurons in the central nucleus of the amygdala (CeA)

Take Home Endogenous NPS has a dual function to acutely attenuate anxiety-like responses and later facilitate extinction of aversive memories

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